1. EVOLUTION, SEXUAL REPRODUCTION, SEXUAL DIMORPHISM, AND REPRODUCTIVE STRATEGIES

2. Asexual (Not Sexual) reproduction 46

3. Asexual reproduction was the only kind of reproduction from the time of the origin of life on earth, about 4.5 billion years ago, up to about 1-1.2 billion years ago, when sexual reproduction arose.

4. Today: Asexual Reproduction is limited to: 1.Prokaryotic organisms 2.Protistas 3.Fungus – Most have sexual as well. 4.Few plants – Most have sexual reproduction as well. 5.One or two animals

5. Prokaryotic cells Protista Animal - Hydra simple Cnidaria Plant – Grass that has runners

6. Sexual Reproduction 46 23 Sperm or Eggs

9. Meiosis and Mitosis Compared Egg or Sperm (23 Chromosomes )

10. Human Chromosomes Male and Females both have 46 chromosomes 44 of them are autosomes 2 are sex chromosomes Females have XX Males have XY

11. Human female karyotype Sex Chromosomes

12. Human male karyotype Sex Chromosomes

13. Eggs have 23 chromosomes 22 are autosomes 1 is an X (sex) chromosome Sperm have 23 chromosomes 22 are autosomes The sex chromosome can be either an X or a Y

14. Eggs (Ova) are large and carry a lot of nutrients (23 chromosomes) Sperm are small and motile – DNA with a delivery system (23 chromosomes)

15. Advantages of Asexual Reproduction No partner needed Less energy required to produce flowers, gonads, pheromones, etc. Exact copy is made. So, if it works, why change it?

16. Advantages of Sexual Reproduction Variation More varieties help enable the species to survive in a changing environment.

17. Sexual Dimorphism Physical characteristics that differ in males and females of the same species.

18. Size

19. Coloration

20. Fig. 12-06

21. Bill Size

25. Teeth and size

26. Horns

31. Explanations for the evolution of sexual dimorphism 1.Intrasexual selection 2.Intersexual selection 3.Post-mating selection

32. Intrasexual Selection Male/Male competition

33. Fig. 12-09

34. Usually one dominant male

35. Intersexual selection

36. Post-mating selection

37. In case you think all species have sexually dimorphic sex organs - Spotted Hyenas

38. In Primates sexual dimorphism is often related to sexual social behavior SEXUAL SOCIAL RELATIONS: -Monogamy – one mate for life -Polygamy – males have multiple partners -Polyandry – Females have multiple partner

39. Monogamy when males and females have little or no sexual dimorphism

40. Polygamy

42. Polyandry

44. STUDY GUIDE FOR LECTURE I -Sexual reproduction (Meiosis) -Asexual reproduction (Mitosis) -How do they differ and what are the advantages and disadvantages of each -Sexual dimorphism – Examples and significance -Inter-sexual Selection – examples of characteristics and particular animals that exhibit this. -Intra-sexual Selection – examples of characteristics and particular animals that exhibit this. -Post-mating Selection – what characteristic does this explain. -How do sexually dimorphic characteristics in primates relate to sexual social behavior and give examples of each.